Reversible idiopathic acute renal failure in children with primary nephrotic syndrome.

We describe the clinical features of four pediatric patients (20 months to 10 years of age) in whom reversible idiopathic acute renal failure (RIARF) developed during the course of primary nephrotic syndrome (PNS). All patients had severe PNS and were in relapse at the onset of RIARF. This complication of PNS was preceded by primary peritonitis in three of four patients. Renal biopsy done in the early phases of RIARF showed tubular epithelial changes similar to those observed in acute tubular ischemia. All patients required dialysis. Recovery of renal function followed fluid removal in three of four patients. The RIARF lasted from 12 days to 1 year and was followed by complete recovery of renal function in all patients. We conclude that (1) RIARF is a potential complication in children with severe PNS, (2) RIARF is associated with primary ischemic renal tubular injury, and (3) recognition of the reversibility of this complication of PNS could alter long-term plans for management of renal failure in these patients.